Field of the Disclosure
The present disclosure relates to an insoluble cesium glass ceramic which is intended to be a replacement for cesium chloride or similar materials used as radiation sources.
Description of the Prior Art
Cesium-137 chloride is used as a radiation source in many different applications, such as, but not limited to, medical and industrial (gaging) applications. Cesium-137 chloride typically has a specific activity of 100 Curies per cubic centimeter and is used in hospitals and universities across the world. In the United States alone there are at least 1300 high activity cesium chloride sources in use. As cesium chloride is soluble in water, it can present difficult radiological challenges. At least three European countries have banned the use of cesium chloride radiological sources. The National Research Council has recommended Congress and the NRC to stop licensing new cesium chloride sources and provide incentives for users to trade out their in-use or spent sources. The committee report notes that although less hazardous forms of cesium exist, none are commercially available.
While cesium-137 chloride's specific activity is approximately 2.98 gCs/cc, its effective specific activity can only be 20-30% less because it undergoes a phase transition at 451° Centigrade which results in a 17% increase in volume.
In 2011, a new application for cesium niobate was devised (Solid-State Photocatalysts). The Department of Energy researchers devised a medium temperature synthesis method to produce cesium niobate using a Sol-Gel technique.
Related prior art includes U.S. Pat. No. 3,330,697 entitled “Method of Preparing Lead and Alkaline Earth Titanates and Niobates and Coating Method Using the Same to Form a Capacitor”, issued on Jul. 11, 1967 to Pechini and U.S. Pat. No. 3,567,646 entitled “Stable Cesium Compounds”, issued on Mar. 2, 1971 to Gray.
Protocols of interest are described in:
1. E. R. Camargo and M. Kakihana, Low Temperature Synthesis of Lithium Niobate Powders Based on Water-soluble Niobium Malato Complexes, Solid State Ionics 151 (2002), 413-418.
2. V. Bouquet, E. Lono, E. R. Leite and J. A. Varela, Influence of Heat Treatment on LiNbO3 Thin Films Prepared on Si(111) by the Polymeric Precursor Method, Journal of Material Research 14 (1999), 3115-3121.
3. Progress in Solid State Chemistry Research, edited by Ronald W. Buckley, published by Nova Science Publishers, Inc., 2007, Chapter 3, pages 117-164, entitled Precursors Routes for the Preparation of Nb-Based Multimetallic Oxides authored by D. A. Bayot and M. M. Devillers.
4. E. R. Camargo and M. Kakihana, Chemical Synthesis of Lithium Niobate Powders (LiNbo3) Prepared from Water-Soluble Dl-Malic Acid Complexes, Chemical Materials (2001) 13, 1905-1909.
5. Robert W. Smith, Wai-Ning Mei, Renat Sabirianov, Novel Photocatalytic Metal Oxides, D.O.E. Hydrogen and Fuel Cells Program, FY 2011 Annual Progress Report, 170-172.
6. L. H. Wang, D. R. Yuan, X. L. Duan, X. Q. Wang and F. P. Yu, Synthesis and Characterization of Fine Lithium Niobate Powders by Sol-Gel Method, Crys. Res. Technol. 42, No. 4, 321-324 (2007).